Compact generalized joined coupler matrix with orthogonal beams

Abstract

An analogue beamforming network, such as the Butler matrix can produce orthogonal beams, the peak of each beam being aligned with the nulls of all other beams. This is particularly important in scenarios requiring interference resilience in systems like base stations and user equipment. This paper presents a 3 × 5 Nolen-like generalized joined coupler (GJC) matrix to produce orthogonal beams with both compact size and flexibility. The phase shifters are integrated into couplers while the coupling value range of couplers are extended to achieve the required performance of the GJC matrix. A prototype GJC matrix is designed, simulated, fabricated, and measured. The measured results agree well with the simulation ones.